Main menu

Article

About the Writer

Kristin Wartman is a journalist focusing on the intersections of food, health, politics, and culture. Her work has appeared in The New York Times, The Atlantic, Huffington Post, and Grist, as well as in academic journals such as Critical Quarterly, The Black Scholar, Tikkun Magazine, and The New Labor Forum. Kristin is also a Certified Nutrition Educator and works as a nutrition consultant with various doctors in New York City.

Post navigation

Not Soy Fast

Thanks to Michael Pollan, many Americans are now aware that when a food boasts a health claim it usually means it’s actually not that healthy after all. But there’s one food that consistently flies below the radar despite its numerous health claims when found in processed and packaged foods: Soy. A long-time staple in the American health food repertoire, it is a prominent example of Pollan’s observation. And the research is mounting that soy foods are not only questionable in terms of their benefits, but in fact, may be hazardous to your health.

Most recently, the Cornucopia Institute conducted research on the processing of soy foods and found that the industry commonly uses hexane—a petroleum-based solvent and known neurotoxin—to process soy ingredients found in many “natural” food products.

Thanks to their research and consumer concern, the Cornucopia Institute announced last week that some companies have voluntarily changed their processing practices and eliminated hexane from their products. Unfortunately, there are still well over two dozen “all-natural” nutrition bars and veggie burgers that still use hexane to process soy.

But hexane processing is really just the tip of the iceberg when it comes to problems associated with eating soy—and many of the health problems are unknown to the general public.

In 1999, the FDA approved the health claim that soy is “heart healthy” and reduces the risk of cardiovascular disease. But this wasn’t without controversy. Two researchers for the FDA, Daniel Doerge and Daniel Sheehan stated that they were opposed to the labeling of foods containing soy as heart healthy since there was “abundant evidence that some of the isoflavones found in soy…demonstrate toxicity in estrogen sensitive tissues and in the thyroid.”

The two researchers refer to numerous studies that show the estrogenic quality of soy isoflavones have harmful effects on many in the population. Isoflavones are a type of phytoestrogen, or plant-based estrogen that mimics human estrogen. It functions similarly to other endocrine disruptors (which I wrote about here on Civil Eats) and binds to our estrogen receptors. Consuming soy elevates estrogen levels, which is correlated with increased risk for breast cancer (and other estrogen-sensitive cancers as well), as 80 percent of U.S. breast cancers are associated with estrogen supplementation. In one study reported in the American Journal of Clinical Nutrition, women who already had breast tumors were given a soy drink for 14 days and their breast tumor growth increased significantly.

In another study the researchers for the FDA refer to, consumption of soy is linked to brain aging, shrinking, and the development of Alzheimer’s disease. In this 35-year Hawaiian study of 8,900 Japanese men and 500 of their wives, tofu intake was the only factor that correlated with an increased occurrence of Alzheimer’s disease. The researchers wrote, “This finding is consistent with the environmental causation suggested from the earlier analysis, and provides evidence that soy (tofu) phytoestrogens causes vascular dementia.”

Perhaps most alarming is the use of soy-based infant formulas. They pose such a risk that the health ministers of the United Kingdom and New Zealand have advised parents not to use soy formula. Studies have found that soy-fed infants have estrogen levels an average of seventeen thousand times higher than infants fed human or cow’s milk.

For men, estrogen-rich soy is also problematic. The Israeli Health Ministry warns men to exercise caution in regards to soy consumption as it has been shown to lower virility—since eating soy reduces testosterone and increases estrogen. In one study presented at the 2007 conference of the American Society of Reproductive Medicine, researchers found that in subfertile men, those eating the most soy had forty-one million fewer sperm per milliliter than those who consumed none. The average amount consumed was equivalent to half a tofu patty. In the womb, excess estrogen causes abnormal sexual development and low sperm counts in boys and men.

As is clear from these studies, the phytoestrogens in soy are quite powerful. While other foods (flaxseed, garbanzo beans, and oats, for example) also contain some amount of phytoestrogens, soy contains the highest amount—and since it is often used in such large quantities as a replacement for meat or dairy, it’s more problematic than other foods. Proponents of soy often refer to the long history of its use in Asian cultures but they fail to mention just how much is typically eaten. In Japan the average amount of soy consumed on a daily basis is two tablespoons, in China it’s two teaspoons where it’s eaten as a condiment rather than a replacement for animal products.

In America however, since soy is in thousands of processed foods (usually in the form of soy protein isolate, soy isoflavones, textured vegetable protein, and soy oils) it accounts for a fifth of the calories in the American diet—not to mention the actual soy foods and drinks that some use as a replacement for meat or dairy. Soy isoflavones were actually denied status as “generally regarded as safe,” or GRAS, as a food additive by the FDA due to the many uncertainties surrounding them. A senior scientist for the FDA wrote, “Confidence that soy products are safe is clearly based more on belief than hard data.”

What’s more, unfermented soy (tofu, soymilk, soy cheese, ice cream, yogurt, soy protein shakes, soy protein isolate) contains high amounts of phytic acid which blocks mineral absorption—particularly calcium, magnesium, iron, and zinc; and soy is an unusual protein that is difficult to digest. Soy is also a goitrogen, meaning it depresses thyroid function and interferes with the absorption of thyroid hormones as well as the crucial mineral iodine.

Fermented soy (miso, natto, tempeh, and soy sauce), most commonly eaten in Asian cultures, is easier to digest and contains far less phytic acid. In addition to choosing fermented soy products over others, choosing organic soy products means avoiding the 91 percent of soybeans produced in this country that are genetically modified and highly contaminated with pesticides.

Why haven’t you heard many of these facts and figures when it comes to “heart healthy” soy? Soy production is a major player in the industrial food system. According to the USDA, in 2009 the total acreage of soybeans planted in the U.S. was 77.5 million acres, accounting for the largest source of protein feed and the second largest source of vegetable oil in the world. In 2008-09, the farm value of soybean production was $29.6 billion, the second highest among U.S. produced crops.

So let’s remember Pollan’s decree: “a health claim on a food product is a good indication that it’s not really food, and food is what you want to eat.” And in fact, this applies to nearly every health claim, even the ones that you might not suspect. It’s good to note, too, that when the food in question is one of the largest players in the industrial food system, you can bet we’re not getting the whole story.

Once again, for everyone who was not paying attention the last time: question authority. FDA, USDA- if you think they are looking out for your health interests you put yourself in a position of vulnerability and risk.

I dated a man 5 yrs ago and he was trying to convince me that GMO food was better for everyone. Instead of spraying the crops, the pesticide was IN the seed..
I just didnt understand on what planet this would ever be “better.”
Then a year ago I was trying to explain to a vegetarian friend that soy was bad and I could hardly find ONE article on the dangers of soy.. (she had breast cancer)
Now the information is amazing!
Thank you!
Rachel

I have always wondered about soy and never embraced it lie some of my friends. Maybe my body just knew it did not need it.When my daughter had to go on a soy free and dairy free diet you quickly realize how soy is in everything. It pays to avoid any processes foods and cook meals using basic ingredients.

This is just another shill piece for the Weston A. Price organization. Before you pass this article on to others, check the qualifications/credentials of this author to make the claims she makes. I’m not dismissing the scientific data, just this author’s interpretation and conclusions. Problems with soy largely stem from those who make money from it. Soy is not magical nor is it evil.
Every issue raised here is addressed in this article (and check these author’s qualifications/credentials) linked below:

The problem is that soy is considered healthy by most. When I say in my office soy is not particularly healthy, I get glazed over looks. Articles like these at least pull the curtains back on this particular myth.

The studies this author is using to form her conclusions are outdated. A large, recent, well-structured mainstream medical study found that eating soy actually reduced tumors and cancer recurrence in breast cancer patients — and the more soy they ate, the better the results. However, it’s a good idea to avoid highly-processed textured soy protein products, which are basically junk food and stick to organic (non-gmo) tofu, tempeh and whole soybeans.

A decidedly one-sided article this is. If one does a bit of research on this subject, one comes away with several conflicting studies on the health benefits of soy. I imagine the hexane-processed soy cannot be the most healthy choice, but when it comes to natural soy sources, both fermented and non-, my come-away conclusion is the same as it is for most foods–moderation.

This article is misleading. Most of the cited studies were conducted using soy isolates and the study that used tofu is seriously flawed. Processed foods are not healthy. We all get that but to infer that all soy foods are unhealthy is disingenuous. The Okinawans eat 4 servings of soy foods a day and have one of the healthiest aging populations on the planet. Stick to organic minimally processed soy and don’t believe the anti-soy hysteria.

Happily, the quackery of naturopathy is illegal to practice (though not to endorse) in my state. Exactly why so many pseudo-authorities have chosen to bash soy I don’t know, though I’m sure the meat industry is an eager accomplice, along with the Wackos at the WAP Foundation. I don’t have time to try to rebut all the misinformation on the web, but, in short, phytoestrogens are NOT estrogens, they just resemble them chemically, and NO studies (note how preciously the text is parsed and how few the minority view authorities actually being quoted) proving that eating soy products has ANY negative effect, and that soybeans can have the very POSITIVE effect of protecting against breast cancer in women IF they begin consuming it in their mid teens. Research it on your own, but beware; there are far more quacks than actual scientists on the web.

You reference the Cornucopia study, but your link doesn’t go to any study — and looking over their site, I don’t see how they’re in a position to finance nutritional research . . . they seem to be an advocacy group for small farms. Link? While checking out the other link for the study you cited from the Univ of Illinois, I found two 2009 studies in the same publication that claim the more unprocessed soy you eat, the less likely you are to get breast cancer and to have breast cancer return if you’ve had it. http://www.ncbi.nlm.nih.gov/pubmed/19403632http://www.ncbi.nlm.nih.gov/pubmed/19996398

“Consuming soy elevates estrogen levels, which is correlated with increased risk for breast cancer (and other estrogen-sensitive cancers as well), as 80 percent of U.S. breast cancers are associated with estrogen supplementation.”

john, i am curious as to what kind of authority has been bestowed upon you so that you feel entitled to call all naturopathy “quackery”. while i agree that not all soy products are unhealthy, foods that contain soy protein isolate are most certainly not the “health foods” they are pretending to be – it is not the soy that is the problem but rather the method of extraction. there is no need to put people down based upon their beliefs or medical practices. this is not an appropriate forum for bashing fellow human beings.

Let’s not overlook potential estrogen-related problems for men..(man boobs are not for everyone). I have three sons, and fortunately, my wife and I never fed them soy products.

I know this is tough on the soy industry, (I have friends who are soy farmers), but should we suppress the unfolding truth in the name of profit? Of course some on this blog would say “yes-by God”. The industry should relax, most of my friends are not alert enough to worry about soy, and often resent hearing the information.

You can tell this is dairy industry propaganda because it goes into paragraph after paragraph about soy phytoestrogens. However, not once does it mention the estrogen in cow milk. Since, most people using soy products are replacing dairy products; they are substituting plant estrogen for the animal estrogen they were eating. My money would be on mammal estrogen being better absorbed and utilized by cancer than plant estrogen. Just like iron in animal tissue is 90% absorbed by humans but plant iron is only 10% available.

You never hear about animal estrogen in dairy products, but rarely a week goes by without some article about soy phytoestrogen. Further, the industrial farms are cranking out milk that is much much higher in estrogen then the milk consumed by our grandparents.

Eliminate all these products if you want. But soy as a replacement for cow milk is probably a net positive. Here is a Harvard study that somehow never made the news…

I’m interested in these findings, but I’m not sure where the author found the information about Asia. My wife lived in Japan for 8 years and we have many friends in Asia. Soy is a major part of the daily diet in Japan, far more than two tablespoons.

Grace, there is no link between men eating soy and getting manboobs, that is laughable at best. It’s the men who eat nothing but hormone laden meat constantly who get manboobs. Anti-Soy Hysteria has been out there for a long time and i find it ridiculous i’m still finding these articles online on good websites, this i all BS, I have been eating tofu everyday of my life since I was 14 and am now 22 and in great shape, and don’t have manboobs.

Thank you for correcting the misinformation contained within this article. It is remarkable that someone would be so careless in writing an article that they would misstate the information that they referenced in these articles. In both cases the misstated information is made to appear severely worse than the referenced article. It is hard to believe that the author of the blog did not deliberately set out to mislead their readers. If the author of this story continues to misstate the results of research painstakingly done by scientists , then it will severely damage the credibility of the author and subsequently the blog that publishes the author’s work.

Believe what you like. I don’t like soy anyway, so I try to avoid it on that basis alone. Plus, my doctor found that I am intolerant of soy protein. I understand that many people find it hard to digest– and I’m apparently one of them. It gives me tummy cramps if I eat too much.

My big beef is that it is liberally used in everything. And there’s no denying that the vast majority of the soy crop is GMO– which has its own set of concerns.

As to the “wackos”? I don’t think that anybody at the Weston A. Price organization has any financial interest whatsoever on whether you eat soy or not. That certainly can’t be said of the very powerful companies like Monsanto, for instance, that stand to profit hugely from increased soy consumption. YMMV.

I am vegan and will continue to eat soy. It is a proven fact that meat and dairy are bad for you. Besides, I will take my chances jsut because I do not want to contribute to the suffering of animals. If I die from eating too much soy at least my conscience will be clear.